Quality of life assessment among HIV-positive persons entering the INSIGHT Strategic Timing of AntiRetroviral Treatment (START) trial

OBJECTIVES

With HIV treatment prolonging survival and HIV infection now managed as a chronic illness, quality of life (QOL) is important to evaluate in persons living with HIV (PLWH). We assessed at study entry the QOL of antiretroviral-naïve PLWH with CD4 counts > 500 cells/μL in the Strategic Timing of AntiRetroviral Treatment (START) clinical trial.

METHODS

QOL was assessed with: (1) a visual analogue scale (VAS) for self-assessment of overall current health; (2) the Short-Form 12-Item Version 2 Health Survey(®) (SF-12V2), for which responses are summarized into eight individual QOL domains plus component summary scores for physical health [the Physical Health Component Summary (PCS)] and mental health [the Mental Health Component Summary (MCS)]. The VAS and eight domain scores were scaled from 0 to 100. Mean QOL measures were calculated overall and by demographic, clinical and behavioural factors.

RESULTS

A total of 4631 participants completed the VAS and 4119 the SF-12. The mean VAS score (with standard deviation) was 80.9 ± 15.7. Mean SF-12 domain scores were lowest for vitality (66.3 ± 26.4) and mental health (68.6 ± 21.4), and highest for physical functioning (89.3 ± 23.0) and bodily pain (88.0 ± 21.4). Using multiple linear regression, PCS scores were lower (P < 0.001) for Asians, North Americans, female participants, older participants, and those with less education, longer duration of known HIV infection, alcoholism/substance dependence and body mass index ≥ 30 kg/m(2) . MCS scores were highest (P < 0.001) for Africans, South Americans and older participants, and lowest for female participants, current smokers and those with alcoholism/substance dependence.

CONCLUSIONS

In this primarily healthy population, QOL was mostly favourable, emphasizing that it is important that HIV treatments do not negatively impact QOL. Self-assessed physical health summary scores were higher than mental health scores. Factors such as older age and geographical region had different effects on perceived physical and mental health.

Effect of HIV infection on tolerability and bacteriologic outcomes of tuberculosis treatment

SETTING

Two international, multicenter Phase 2 clinical trials examining fluoroquinolone-containing regimens in adults with smear-positive pulmonary tuberculosis (TB), conducted from July 2003 to March 2007. Both trials enrolled human immunodeficiency virus (HIV) infected participants who were not receiving antiretroviral therapy (ART) at TB treatment initiation.

OBJECTIVE

To assess the impact of HIV infection on TB treatment outcomes in Phase 2 clinical trials.

DESIGN

Cross-protocol analysis comparing the safety, tolerability and outcomes of anti-tuberculosis treatment by HIV status.

RESULTS

Of 750 participants who received at least one dose of study treatment, 123 (16%) were HIV-infected. Treatment completion rates were similar by HIV status (81% infected vs. 85% non-infected), as were rates of week 8 culture conversion (66% infected vs. 63% non-infected), and treatment failure (5% infected vs. 3% non-infected). Among HIV-infected participants, treatment failure detected using liquid media was more frequent in those treated thrice weekly (14% thrice weekly vs. 2% daily, P = 0.03). HIV-infected participants more frequently experienced an adverse event during the intensive phase treatment than non-HIV-infected participants (30% vs. 15%, P < 0.01).

CONCLUSION

HIV-infected persons not receiving ART had more adverse events during the intensive phase of anti-tuberculosis treatment, but tolerated treatment well. Failure rates were higher among HIV-infected persons treated with thrice-weekly intensive phase therapy.

Pharmacokinetics of ethambutol in children and adults with tuberculosis

SETTING

Five hospitals in the United States.

OBJECTIVE

To describe ethambutol pharmacokinetics in children and adults with active tuberculosis (TB).

DESIGN

Prospective, open-labeled study in 56 adults and 14 children with active tuberculosis who received ethambutol as part of their multidrug TB regimens.

RESULTS

Most serum samples were collected up to 10 h post dose and assayed using a validated gas chromatography assay with mass selective detection (GC/MS). Concentration data were analyzed using non-compartmental and population pharmacokinetic methods. Drug exposure increased with dose, but less than proportionally at doses >3000 mg. Lower than expected maximum serum concentrations (Cmax <2 microg/ml) were common in adults. Very low Cmax (<1 microg/ml) were common in children, as was delayed absorption (time to Cmax >3 h). Many Cmax were at or below typical TB minimal inhibitory concentrations. Cmax values for HIV-positive patients were 20% lower than HIV-negative patients with daily doses, but were similar with larger twice-weekly doses.

CONCLUSIONS

Adult TB patients often had lower than expected ethambutol serum concentrations, and most pediatric TB patients had very low ethambutol serum concentrations. Higher doses and therapeutic drug monitoring may be indicated for many of these patients.

Lack of toxicity from concomitant directly observed disulfiram and isoniazid-containing therapy for active tuberculosis

We retrospectively evaluated the use of disulfiram among alcoholic patients being treated for active tuberculosis. There were 13 alcoholics treated with disulfiram, 105 alcoholics not on disulfiram, and 249 non-alcoholics. Rates of toxicity were higher among alcoholics than among non-alcoholics (58% vs. 32%), but there was no difference between alcoholics taking and those not taking disulfiram (61% vs. 57%). There were no neurological side effects in the disulfiram group. Disulfiram appeared to be safe when added to intermittent, directly observed isoniazid-containing tuberculosis treatment, and was useful in managing complications of alcohol abuse. However, the small number of patients on disulfiram limits the strength of this negative finding.

Comparative pharmacokinetics and pharmacodynamics of the rifamycin antibacterials

The rifamycin antibacterials, rifampicin (rifampin), rifabutin and rifapentine, are uniquely potent in the treatment of patients with tuberculosis and chronic staphylococcal infections. Absorption is variably affected by food; the maximal concentration of rifampicin is decreased by food, whereas rifapentine absorption is increased in the presence of food. The rifamycins are well-known inducers of enzyme systems involved in the metabolism of many drugs, most notably those metabolised by cytochrome P450 (CYP) 3A. The relative potency of the rifamycins as CYP3A inducers is rifampin > rifapentine > rifabutin; rifabutin is also a CYP3A substrate. The antituberculosis activity of rifampicin is decreased by a modest dose reduction from 600 to 450mg. This somewhat surprising finding may be due to the binding of rifampicin to serum proteins, limiting free, active concentrations of the drug. However, increasing the administration interval (after the first 2 to 8 weeks of therapy) has little effect on the sterilising activity of rifampicin, suggesting that relatively brief exposures to a critical concentration of rifampicin are sufficient to kill intermittently metabolising mycobacterial populations. The high protein binding of rifapentine (97%) may explain the suboptimal efficacy of the currently recommended dose of this drug. The toxicity of rifampicin is related to dose and administration interval, with increasing rates of presumed hypersensitivity with higher doses combined with administration frequency of once weekly or less. Rifabutin toxicity is related to dose and concomitant use of CYP3A inhibitors. The rifamycins illustrate the complexity of predicting the pharmacodynamics of treatment of an intracellular pathogen with the capacity for dormancy.

Population pharmacokinetics of intravenous and intramuscular streptomycin in patients with tuberculosis

STUDY OBJECTIVES

To determine population pharmacokinetic parameters of streptomycin after administration of multiple intramuscular and intravenous doses.

DESIGN

Prospective, unblinded clinical study.

SETTING

Two medical centers in Denver, Colorado.

PATIENTS

Thirty patients with tuberculosis.

INTERVENTION

Patients received multiple doses of streptomycin as part of their tuberculosis treatment. They received concurrent drugs based on in vitro susceptibility data.

MEASUREMENTS AND MAIN RESULTS

Serum samples were collected over a 10-hour period and assayed by validated high-performance liquid chromatography Concentration-time data were analyzed using population methods. Streptomycin concentrations increased linearly with increasing intravenous doses. The intramuscular doses did not produce as linear a relationship, presumably because of variability in rates of and, potentially, completeness of absorption. Streptomycin elimination decreased with declining renal function. Higher, intermittent doses were well tolerated and appeared to maximize the peak concentration:minimal inhibitory concentration ratio.

CONCLUSION

Overall, pharmacokinetic parameters of streptomycin were comparable with those previously published for streptomycin and other aminoglycosides. Higher, intermittent doses maximize pharmacodynamic parameter estimates and might have advantages for treatment of tuberculosis.

The effect of changes in laboratory practices on the rate of false-positive cultures for Mycobacterium tuberculosis

CONTEXT

False-positive cultures for Mycobacterium tuberculosis have been found in nearly all DNA fingerprinting studies, but the effectiveness of interventions to reduce cross-contamination has not been evaluated.

OBJECTIVE

To evaluate whether changes in laboratory policies and procedures reduced the rate of false-positive cultures.

DESIGN

Retrospective study of isolates with matching DNA fingerprints.

SETTING

A mycobacteriology laboratory serving an urban tuberculosis control program and public hospital system.

PATIENTS

All M tuberculosis isolates processed from July 1994 to December 1999.

METHODS

Isolates were fingerprinted using IS6110; pTBN12 was used to fingerprint isolates having fewer than 6 copies of IS6110. We further evaluated all patients having only one positive culture whose DNA fingerprint matched that of another isolate processed in the laboratory within 42 days.

INTERVENTIONS

We changed laboratory policy to reduce the number of smear-positive specimens processed and changed laboratory procedures to minimize the risk of cross-contamination during batch processing.

MAIN OUTCOME MEASURE

The rate of false-positive cultures.

RESULTS

Of 13 940 specimens processed during the study period, 630 (4.5%) from 184 patients and 48 laboratory proficiency specimens grew M tuberculosis. There were no cases (0/184) of probable or definite cross-contamination, compared with the 4% rate (8/199) identified in our previous study (P =.008). We also fingerprinted a convenience sample of isolates from other laboratories in Denver; 13.6% (3/22) of these were false-positive, a rate similar to the 11.9% rate (5/42) identified for other laboratories in our previous study (P =.84).

CONCLUSIONS

Laboratory cross-contamination decreased significantly after relatively simple, inexpensive changes in laboratory policies and practices. Cross-contamination continued to occur in other laboratories in Denver.

Inactivated pronase as the cause of false-positive results of serum cryptococcal antigen tests

Four patients who had acquired immunodeficiency syndrome and who were evaluated for headache within a 3-week period had false-positive results of serum cryptococcal antigen tests. This cluster of false-positive test results appeared to be due to inactivation of the pronase vial in the test kit, a cause that has not been reported previously.

Breaking the camel's back: multicenter clinical trials and local institutional review boards

Clinical research has undergone remarkable and beneficial expansion in the past 25 years, but with this growth has come an unprecedented increase in workload for the human subjects protection system. Recently, a major change in federal oversight of local institutional review boards (IRBs) became evident. Although it was not announced publicly, in 1998 and 1999 federal regulatory actions against local IRBs increased threefold. Particularly notable was the marked increase in regulatory actions taken against the IRBs of academic medical centers (1 in 1997 compared with 14 in 1999). Ironically, this apparent federal crackdown began at the same time that two federal review panels called for major changes in the regulations governing local IRBs. A key factor in the current crisis in the function of local IRBs is the ascendance of multicenter clinical trials as the dominant form of clinical research. Local IRBs were not designed to handle the initial evaluation and ongoing review required by the rapidly increasing number of multicenter clinical trials. Furthermore, local IRB review of the thousands of safety reports from multicenter clinical trials monopolizes resources without promoting patient safety. Instead of rigid enforcement of outmoded regulations that do not contribute to patient safety, the responsibilities of the local IRB in the oversight of multicenter clinical trials must be systematically evaluated.

Review of false-positive cultures for Mycobacterium tuberculosis and recommendations for avoiding unnecessary treatment

We reviewed reports of false-positive cultures for Mycobacterium tuberculosis and here propose guidelines for detecting and managing patients with possible false-positive cultures. Mechanisms of false-positive cultures included contamination of clinical devices, clerical errors, and laboratory cross-contamination. False-positive cultures were identified in 13 (93%) of the 14 studies that evaluated > or = 100 patients; the median false-positive rate was 3.1% (interquartile range, 2.2%-10.5%). Of the 236 patients with false-positive cultures reported in sufficient detail, 158 (67%) were treated, some of whom had toxicity from therapy, as well as unnecessary hospitalizations, tests, and contact investigations. Having a single positive culture was a sensitive but nonspecific criterion for detecting false-positive cultures. False-positive cultures for M. tuberculosis are not rare but are infrequently recognized by laboratory and clinical personnel. Laboratories and tuberculosis control programs should develop procedures to identify patients having only 1 positive culture. Such patients should be further evaluated for the possibility of a false-positive culture.

Epidemiology of Pneumocystis carinii pneumonia in an era of effective prophylaxis: the relative contribution of non-adherence and drug failure

OBJECTIVE

To determine the relative contribution of patient non-adherence, provider failure to prescribe prophylaxis, and drug failure to the continued occurrence of Pneumocystis carinii pneumonia (PCP), and to determine correlates of non-adherence.

DESIGN

Retrospective case-control study.

METHODS

Patients with confirmed or presumptive PCP from May 1995 to September 1997 who had at least 6 months of prior HIV care (cases) were compared to controls matched for initial CD4 cell count and date of initial HIV care.

RESULTS

The incidence of PCP declined by 85% in the 28 months of the study. Of the 118 cases of PCP identified, 59 (50%) were in HIV care for > 6 months prior to PCP diagnosis. In a multivariate logistic regression model, risk factors for PCP among patients in HIV care were patient non-adherence [odds ratio (OR), 12.4; 95% confidence interval (CI), 6.4-23.5], use of prophylaxis other than trimethoprim-sulfamethoxazole (OR, 27.0; 95% CI, 13.8-52.9), and absence of antiretroviral use (OR, 7.5; 95% CI, 4.5-12.5). Provider non-adherence occurred in one out of 59 cases (2%), and five out of 106 controls (5%). Of the patients who developed PCP on prophylaxis, 18 cases (30%) appeared due to drug failure; there were no cases of apparent drug failure among patients on trimethoprim-sulfamethoxazole. In multivariate analysis, non-adherence was more common among patients of non-white race, those with a history of injecting drug use, and those with active substance abuse or psychiatric illness.

CONCLUSIONS

Patient non-adherence was the most common reason for the occurrence of PCP among patients in HIV care; provider non-adherence was uncommon. Drug failure occurred only among patients on prophylaxis other than trimethoprim-sulfamethoxazole.

Discontinuation of prophylaxis against Mycobacterium avium complex disease in HIV-infected patients who have a response to antiretroviral therapy. Terry Beirn Community Programs for Clinical Research on AIDS

BACKGROUND

Several agents are effective in preventing Mycobacterium avium complex disease in patients with advanced human immunodeficiency virus (HIV) infection. However, there is uncertainty about whether prophylaxis should be continued in patients whose CD4+ cell counts have increased substantially with antiviral therapy.

METHODS

We conducted a multicenter, double-blind, randomized trial of treatment with azithromycin (1200 mg weekly) as compared with placebo in HIV-infected patients whose CD4+ cell counts had increased from less than 50 to more than 100 per cubic millimeter in response to antiretroviral therapy. The primary end point was M. avium complex disease or bacterial pneumonia.

RESULTS

A total of 520 patients entered the study; the median CD4+ cell count at entry was 230 per cubic millimeter. In 48 percent of the patients, the HIV RNA value was below the level of quantification. The median prior nadir CD4+ cell count was 23 per cubic millimeter, and 65 percent of the patients had had an acquired immunodeficiency syndrome-defining illness. During follow-up over a median period of 12 months, there were no episodes of confirmed M. avium complex disease in either group (95 percent confidence interval for the rate of disease in each group, 0 to 1.5 episodes per 100 person-years). Three patients in the azithromycin group (1.2 percent) and five in the placebo group (1.9 percent) had bacterial pneumonia (relative risk in the azithromycin group, 0.60; 95 percent confidence interval, 0.14 to 2.50; P=0.48). Neither the rate of progression of HIV disease nor the mortality rate differed significantly between the two groups. Adverse effects led to discontinuation of the study drug in 19 patients assigned to receive azithromycin (7.4 percent) and in 3 assigned to receive placebo (1.1 percent; relative risk, 6.6; P=0.002).

CONCLUSIONS

Azithromycin prophylaxis can safely be withheld in HIV-infected patients whose CD4+ cell counts have increased to more than 100 cells per cubic millimeter in response to antiretroviral therapy.

Comparison testing of current (PPD-S1) and proposed (PPD-S2) reference tuberculin standards

Since 1951, the tuberculin PPD-S1 has been used to standardize commercial PPD reagents and perform special tuberculin surveys. PPD-S1 is now in short supply and a new standard (PPD-S2) has been manufactured. To determine if PPD-S2 is equivalent and can replace PPD-S1, we conducted a double-blind clinical trial. Between May 14 and October 28, 1997, 69 subjects with a history of culture-proven tuberculosis (TB patients) and 1,189 subjects with a very low risk for TB infection were enrolled, received four skin tests (with PPD-S1, PPD-S2, and one each of the commercially available PPDs), and had reactions measured by two trained observers. Among the TB patients, we found statistically indistinguishable immunogenicity (mean reaction size +/- standard deviation): 15.6 +/- 6.6 mm for PPD-S1 and 14.8 +/- 5.6 mm for PPD-S2. Among low-risk subjects, the tests had equally high specificities (PPD-S1, 98.7% and PPD-S2, 98. 5%), using a 10-mm cutoff. The number of discordant (negative versus positive) interpretations for PPD-S2, assuming that low-risk subjects who had a >/= 10 mm reaction to PPD-S1 were truly infected, was low (0.5%) and indistinguishable from the rate of discordant interpretations of the same test when read by two different observers (0.8%). The study results indicate that PPD-S2 is qualified to be used as the new U.S. reference standard for PPD tuberculin.

Long-term outcomes of treatment of Mycobacterium avium complex bacteremia using a clarithromycin-containing regimen

OBJECTIVES

To describe the long-term outcomes of treatment of AIDS-related Mycobacterium avium complex (MAC) bacteremia using a standard clarithromycin-based regimen.

DESIGN

Retrospective study of patients with MAC bacteremia diagnosed between April 1992 and April 1995.

SETTING

An urban AIDS clinic

SUBJECTS

One hundred seventy-six consecutive patients with MAC bacteremia.

INTERVENTIONS

Clarithromycin 500 mg twice daily, ethambutol 800 or 1200 mg daily, and clofazimine 100 mg daily.

MAIN OUTCOME MEASURES

Late treatment failure (defined as a positive blood culture more than 90 days after starting treatment), clarithromycin susceptibility of initial and treatment-failure isolates, DNA fingerprinting of isolates from treatment failures.

RESULTS

Two out of 176 (1.1%) baseline isolates were resistant to clarithromycin. One hundred and fifty-one patients were treated for MAC bacteremia, 144 (95%) with the standard regimen. Of the 117 patients who survived > 90 days after starting therapy, 25 (21%) met the criteria for late treatment failure. Of the 22 treatment-failure isolates available for susceptibility testing, 19 (86%) were resistant to clarithromycin. Therefore, 13% of patients treated using the standard regimen (19 out of 144) had treatment failure associated with the emergence of clarithromycin resistance. Using logistic regression, non-compliance was associated with treatment failure (P = 0.02). Fourteen out of the 17 (82%) evaluable paired isolates had identical DNA fingerprint patterns, whereas three pairs showed that a different strain of MAC was present at the time of treatment failure.

CONCLUSIONS

Initial resistance to clarithromycin was rare during this period. However, late treatment failure associated with the emergence of clarithromycin resistance was relatively common during long-term follow-up. Most late treatment failures represented emergence of clarithromycin resistance in the initial strain.

Streptomyces pneumonia in a patient with human immunodeficiency virus infection: case report and review of the literature on invasive streptomyces infections

Streptomyces species are most widely known for their production of antimicrobial substances and, apart from mycetoma, have rarely been reported as a cause of infection. We describe a patient with early human immunodeficiency virus infection who presented with fever, cough, and nodular pulmonary infiltrates. Open lung biopsy revealed necrotic tissue and a sulfur granule; aerobic bacterial cultures yielded Streptomyces species. The patient was treated successfully with clarithromycin for 6 months. We review the clinical presentation and treatment of invasive streptomyces infections.

AIDS-related Mycobacterium kansasii infection with initial resistance to clarithromycin

Clarithromycin is a promising drug for the treatment of Mycobacterium kansasii infection. We report a patient with AIDS and severe M. kansasii infection who had previously received a short course of clarithromycin for sinusitis. He had clinical failure of treatment using clarithromycin plus ethambutol, and the initial isolate was found to be highly resistant to clarithromycin. Nucleotide sequencing of the 23S rRNA gene of this isolate demonstrated a single base mutation at position 2058, the same as that found in clarithromycin-resistant Mycobacterium avium.

Septic shock from Mycobacterium tuberculosis after therapy for Pneumocystis carinii

Septic shock resulting from Mycobacterium tuberculosis (TB) occurs only rarely, even among patients infected with human immunodeficiency virus. We report a case of fulminant TB sepsis in the setting of human immunodeficiency virus infection. This case illustrates the hazards of corticosteroid use as a part of empirical treatment of Pneumocystis carinii pneumonia, as well as the unique appearance of TB on chest x-ray films.

Anterior uveitis and hypotony after intravenous cidofovir for the treatment of cytomegalovirus retinitis

OBJECTIVE

This study aimed to describe the incidence and risk factors for the development of anterior uveitis in patients receiving intravenous cidofovir for the treatment of longstanding cytomegalovirus retinitis.

DESIGN

The study design was a retrospective cohort.

PARTICIPANTS

Eighteen patients (30 eyes) receiving parenteral cidofovir for the treatment of complicated cytomegalovirus retinitis participated.

MAIN OUTCOME MEASURES

The clinical response to parenteral cidofovir; the occurrence of anterior uveitis, and the management and outcome of patients with this complication; and the effect of cidofovir on intraocular pressure measurements were measured.

RESULTS

There was no progression or relapse of retinitis in patients receiving intravenous cidofovir. Eight (44%) of the 18 patients developed anterior uveitis, which occurred after a median of 4 doses of intravenous cidofovir. The median CD4+ cell count at the time of development of iritis was 101/mm3. Patients who developed uveitis had a mean increase in serum creatinine over baseline measurements (P = 0.05). The use of human immunodeficiency virus type-1 (HIV-1) protease inhibitors was not different between both groups of patients (P = 1.0). The development of anterior uveitis and visually significant hypotony necessitated withdrawal of cidofovir in only one patient.

CONCLUSIONS

Anterior uveitis was a common complication after intravenous cidofovir therapy. Despite the frequency of this complication, continued treatment with intravenous cidofovir was possible in the majority of patients. Patients with anterior uveitis after intravenous cidofovir may be treated successfully with topical corticosteroid therapy and cycloplegic agents.

Evaluation of a disk diffusion method for determining susceptibility of Mycobacterium avium complex to clarithromycin

We evaluated an agar disk diffusion method for determining the susceptibility of Mycobacterium avium complex to clarithromycin. Isolates were inoculated onto the surface of a Middlebrook 7H11 plate, followed by the application of a 15-microgram clarithromycin disk. Zone sizes were read after 5-7 days of incubation. Zone sizes had a bimodal distribution; 40 isolates (10%) had no zone of inhibition, whereas the zone sizes for the remaining isolates ranged from 11 to 60 mm. Most isolates (37/40) having no zone of inhibition came from patients who had been treated previously with clarithromycin. Fifty-one isolates were also tested for clarithromycin susceptibility using a microdilution broth method. Defining susceptibility as a zone size of > 10 mm, disk diffusion test results agreed with the results by the microdilution broth method for 50 of 51 (98%) isolates tested by both methods. Agar disk diffusion is a promising method for the determination of clarithromycin susceptibility testing for M. avium complex.

A cost-effectiveness analysis of directly observed therapy vs self-administered therapy for treatment of tuberculosis

STUDY OBJECTIVES

To compare the costs and effectiveness of directly observed therapy (DOT) vs self-administered therapy (SAT) for the treatment of active tuberculosis.

DESIGN

Decision analysis.

SETTING

We used published rates for failure of therapy, relapse, and acquired multidrug resistance during the initial treatment of drug-susceptible tuberculosis cases using DOT or SAT. We estimated costs of tuberculosis treatment at an urban tuberculosis control program, a municipal hospital, and a hospital specializing in treating drug-resistant tuberculosis.

OUTCOME MEASURES

The average cost per patient to cure drug-susceptible tuberculosis, including the cost of treating failures of initial treatment.

RESULTS

The direct costs of initial therapy with DOT and SAT were similar ($1,206 vs $1,221 per patient, respectively), although DOT was more expensive when patient time costs were included. When the costs of relapse and failure were included in the model, DOT was less expensive than SAT, whether considering outpatient costs only ($1,405 vs $2,314 per patient treated), outpatient plus inpatient costs ($2,785 vs $10,529 per patient treated), or outpatient, inpatient, and patients' time costs ($3,999 vs $12,167 per patient treated). Threshold analysis demonstrated that DOT was less expensive than SAT through a wide range of cost estimates and clinical event rates.

CONCLUSION

Despite its greater initial cost, DOT is a more cost-effective strategy than SAT because it achieves a higher cure rate after initial therapy, and thereby decreases treatment costs associated with failure of therapy and acquired drug resistance. This cost-effectiveness analysis supports the widespread implementation of DOT.

Short-term incarceration for the management of noncompliance with tuberculosis treatment

STUDY OBJECTIVES

To review the use of incarceration for noncompliance with tuberculosis treatment.

DESIGN

Retrospective review.

SETTING

An urban tuberculosis control program.

PATIENTS

Patients treated for active tuberculosis.

MEASUREMENTS AND RESULTS

We reviewed the legal basis and practical application of quarantine for active tuberculosis, including the use of incarceration for noncompliance. The records of patients treated at the Denver Metro Tuberculosis Clinic during 1984 to 1994 were reviewed to identify patients who were incarcerated and to evaluate the effectiveness of this intervention. Of 424 cases of tuberculosis, 20 patients (4.7%) were incarcerated for noncompliance; an additional 21 patients (5.0%) were lost to follow-up prior to completing therapy. Incarcerated patients were predominantly men who were born in the United States and had a history of homelessness and alcohol abuse. The median duration of the initial incarceration was 20 days (range, 7 to 51 days). Of the 17 patients released prior to completing therapy, 13 (76%) were compliant with outpatient, directly observed therapy after one or two short-term incarcerations (<60 days); only three patients were incarcerated for the duration of treatment. Overall, 18 of 20 incarcerated patients (90%) were successfully treated.

CONCLUSIONS

Approximately 5% of the patients treated through our program were incarcerated for noncompliance; an additional 5% were unavailable for follow-up and would have been candidates for incarceration if found. Homelessness and alcoholism were closely associated with the use of incarceration. Short-term incarceration followed by outpatient, directly observed therapy was relatively successful in the management of this difficult patient population.

The value of in vitro drug activity and pharmacokinetics in predicting the effectiveness of antimycobacterial therapy: a critical review

Marked increases in case rates of drug-resistant tuberculosis and nontuberculous mycobacterial infections have brought renewed urgency to the development of new treatment regimens for mycobacterial infections. Preclinical data, such as in vitro measures of drug activity and pharmacokinetics, are used in the design of new treatment regimens. This review surveys the extensive published clinical experience concerning the treatment of drug-susceptible tuberculosis to evaluate the use of these preclinical measures in predicting clinical outcomes of antimycobacterial therapy. In vitro measures of drug activity predict the potency of a drug to prevent the emergence of resistance to other antimycobacterial drugs but do not predict the sterilizing activity of a drug or the activity of drug combinations. In vitro measures of drug activity do not allow reliable predictions of the level at which an organism should be considered resistant. Assays of drug penetration in tissues and activity against intracellular bacilli add modestly to the predictive value of in vitro measures of drug activity but still do not predict sterilizing activity. In contrast, animal models of tuberculosis have predicted relative drug potency (including sterilizing activity), the efficacy of multidrug regimens, and the duration of therapy needed. Despite pharmacokinetic parameters that would suggest the need for multiple doses per day, all of the first-line antituberculous drugs are active when given as infrequently as twice weekly. It is difficult to predict the efficacy of therapy for an intracellular pathogen that has the capacity for dormancy. Better in vitro models are needed, particularly ones that predict sterilizing activity.

Comparison of BACTEC 12B vs solid media for the recovery of Mycobacterium avium complex from blood cultures in AIDS patients

We compared liquid (BACTEC 12B) and solid culture media for the diagnosis of Mycobacterium avian complex (MAC) bacteremia among 258 AIDS patients with a positive blood culture. Neither culture media alone had adequate sensitivity; BACTEC 12B detected growth earlier. Use of both liquid and solid media may improve the yield of mycobacterial blood culture.

Noncompliance with directly observed therapy for tuberculosis. Epidemiology and effect on the outcome of treatment

STUDY OBJECTIVES

To describe the epidemiology and clinical consequences of noncompliance with directly observed therapy (DOT) for treatment of tuberculosis.

DESIGN

Retrospective review.

SETTING

An urban tuberculosis control program that emphasizes DOT.

PATIENTS

All patients treated with outpatient DOT from 1984 to 1994.

MEASUREMENTS AND RESULTS

We defined noncompliance as follows: (1) missing > or = 2 consecutive weeks of DOT; (2) prolongation of treatment > 30 days due to sporadic missed doses; or (3) incarceration for presenting a threat to public health. Poor outcomes of therapy were defined as a microbiologic or clinical failure of initial therapy, relapse, or death due to tuberculosis. Fifty-two of 294 patients (18%) who received outpatient DOT fulfilled one or more criteria for noncompliance. Using multivariate logistic regression, risk factors for noncompliance were alcohol abuse (odds ratio, 3.0; 95% confidence interval, 1.2 to 7.5; p = 0.02) and homelessness (odds ratio, 3.2; 95% confidence interval, 1.5 to 7.2; p = 0.004). Noncompliant patients had poor outcomes from the initial course of therapy more often than compliant patients: 17 of 52 (32.7%) vs 8 of 242 (3.3%); relative risk was 9.9; 95% confidence interval was 4.5 to 21.7 (p < 0.001).

CONCLUSIONS

In an urban tuberculosis control program, noncompliance with DOT was common and was closely associated with alcoholism and homelessness. Noncompliance was associated with a 10-fold increase in the occurrence of poor outcomes from treatment and accounted for most treatment failures. Innovative programs are needed to deal with alcoholism and homelessness in patients with tuberculosis.

A retrospective comparison of clarithromycin versus rifampin in combination treatment for disseminated Mycobacterium avium complex disease in AIDS: clarithromycin decreases transfusion requirements

SETTING

Urban county medical center.

OBJECTIVE

To compare clinical outcomes associated with two treatment regimens for AIDS-associated disseminated Mycobacterium avium complex (DMAC). From 1989 to mid-1992, patients were treated with rifampin, ethambutol, and clofazimine; in mid-1992 clarithromycin replaced rifampin.

DESIGN

A retrospective review of patients with DMAC; the main outcome measures assessed were toxicity associated with DMAC treatment, transfusions after the diagnosis of DMAC, and survival.

RESULTS

88 patients received the rifampin-based regimen and 86 were treated with the clarithromycin-based regimen. Drug-related adverse events were recorded less frequently with clarithromycin treatment (21% vs. 42%, P = 0.005), and additional antimycobacterial agents were used less often (28% vs. 44%, P = 0.04). In a multivariate logistic regression model, severe anemia at the time of DMAC diagnosis was associated with transfusion-dependence (relative risk [RR] 5.6, 95% confidence interval [CI] 2.2, 13.8, P < 0.001) and clarithromycin treatment was inversely associated with transfusion dependence (RR 0.4, 95% CI 0.1, 0.98, P = 0.04). In a multivariate Cox regression model including other factors affecting survival, clarithromycin treatment did not confer a survival advantage (P = 0.74).

CONCLUSIONS

The clarithromycin-containing regimen was better tolerated and was associated with substantially lower transfusion requirements than the rifampin-based regimen; survival was not affected.

The diagnostic yield of acid-fast-bacillus smear-positive sputum specimens

The yield of mycobacterial culture from acid-fast-bacillus smear-positive sputum specimens was 387 or 439 (88.2%). Forty-nine of 52 culture-negative specimens came from patients on treatment. We conclude that the yield of culture from smear-positive sputum specimens is very high and that only two acid-fast-bacillus smear-positive specimens are needed for the initial evaluation of pulmonary mycobacteriosis.

DNA fingerprinting with two probes decreases clustering of Mycobacterium tuberculosis

DNA fingerprinting of Mycobacterium tuberculosis is used to study the epidemiology of tuberculosis, but the specificity of the widely used IS6110 technique has not been validated. Isolates from Denver, Colorado from December 1988 through June 1994 were fingerprinted with the IS6110 technique. Available records were reviewed for patients whose isolates were within IS6110-defined clusters, and these isolates were fingerprinted with an independent technique (pTBN12). Of 189 isolates, 86 (46%) were in IS6110-defined clusters. Clustering was inversely related to the number of copies of IS6110, ranging from 12 of 12 (100%) to 37 of 48 (77%) and 37 of 129 (29%) for isolates having one, two to five, and more than five copies (p < 0.001). Of the 86 isolates clustered with the IS6110 technique, 35 (41%) had unique pTBN12 fingerprints. Discordant results with the two fingerprinting techniques were more common among isolates having five or fewer copies of IS6110. Epidemiologic links were identified among four of 35 (11%) patients whose isolates had discordant fingerprinting results, as compared with 40 of 51 (78%) of those whose isolates matched by both IS6110 and pTBN12. DNA fingerprinting with the IS6110 technique was not a specific marker of DNA clonality, particularly among isolates having fewer than five copies of IS6110. The use of a supplemental DNA fingerprinting technique decreased clustering and improved the correlation between the transmission links predicted by molecular techniques and epidemiologic investigation.

The incidence of false-positive cultures for Mycobacterium tuberculosis

The frequency of false-positive cultures for Mycobacterium tuberculosis due to cross-contamination has been difficult to determine because of the lack of specific strain markers. Isolates collected prospectively over 5 yr from a municipal health department laboratory underwent DNA fingerprinting using the IS6110 and pTBN12 sequences. We reviewed the clinical and laboratory records of all isolates that had matching DNA fingerprints and were processed within 42 d of each other; 8 isolates were classified as probable or definite false-positives, representing 4.0% (8/199) of the culture-positive patients. A convenience sample of 42 isolates from three other mycobacterial laboratories also underwent DNA fingerprinting, and five (12%) were found to be definite or probable false-positives. Cross-contamination during initial processing of specimens was the most common source of false-positive cultures. The source of cross-contamination for three false-positive cultures was a laboratory proficiency survey specimen containing strain H37Ra. Ten of the 13 patients were misdiagnosed as having tuberculosis, and seven received unnecessary multidrug treatment. Clinicians should be aware of the potential for false-positive cultures for M. tuberculosis, and mycobacteriology laboratories need to carefully review procedures to minimize this occurrence. DNA fingerprinting provides a valuable tool for the study of false-positive cultures.

Evaluation of method for secondary DNA typing of Mycobacterium tuberculosis with pTBN12 in epidemiologic study of tuberculosis

Secondary fingerprinting of Mycobacterium tuberculosis DNA with a probe containing the polymorphic GC-rich repetitive sequence present in pTBN12 has been found to have greater discriminating power than does fingerprinting with the insertion sequence IS6110 for strains carrying few copies of IS6110. To validate the use of pTBN12 fingerprinting in the molecular epidemiology of tuberculosis, M. tuberculosis isolates from 67 patients in five states in the United States and in Spain were fingerprinted with both IS6110 and pTBN12. Epidemiologic links among the 67 patients were evaluated by patient interview and/or review of medical records. The 67 isolates had 5 IS6110 fingerprint patterns with two to five copies of IS6110 and 18 pTBN12 patterns, of which 10 were shared by more than 1 isolate. Epidemiologic links are consistently found among patients whose isolates had identical pTBN12 patterns, whereas no links were found among patients whose isolates had unique pTBN12 patterns. This suggests that pTBN12 fingerprinting is a useful tool to identify epidemiologically linked tuberculosis patients whose isolates have identical IS6110 fingerprints containing fewer than six fragments.

Low antituberculosis drug concentrations in patients with AIDS

OBJECTIVE

To determine the frequency and magnitude of below normal apparent peak serum concentrations for antituberculosis drugs in patients with AIDS and CD4 cell counts less than 200 cells/mm3. We also explored the data for potential relationships between response variables and patient characteristics.

DESIGN

Prospective study of consecutive patients seen in tuberculosis clinics.

SETTING

Five urban tuberculosis clinics in four major metropolitan areas.

PARTICIPANTS

Twenty-six patients diagnosed with HIV infection and receiving treatment for active tuberculosis were eligible.

MAIN OUTCOME MEASURES

After 2 weeks or more of therapy, blood was collected 2 hours after observed doses of the antituberculosis drugs. Serum samples were frozen, shipped to National Jewish Center in Denver, and analyzed by HPLC or GC. Serum concentrations were compared with the proposed normal ranges. Data were analyzed to determine correlations between antituberculosis drug serum concentrations and patient characteristics.

RESULTS

Low-2-hour serum concentrations were common for antituberculosis drugs, particularly rifampin and ethambutol. Absorption of isoniazid was generally high. Potential drug-drug interactions were found between rifampin and fluconazole (fluconazole appears to increase rifampin concentrations) and between pyrazinamide and zidovudine (zidovudine may lower pyrazinamide concentrations). Patients receiving pyrazinamide had lower rifampin concentrations than those not receiving pyrazinamide.

CONCLUSIONS

Low antituberculosis drug serum concentrations occur frequently during the treatment of tuberculosis in patients with AIDS. Additional research is required for patients with drug-resistant tuberculosis, and to clarify the nature of the potential drug-drug interactions.

Usefulness of the secondary probe pTBN12 in DNA fingerprinting of Mycobacterium tuberculosis

A comparison was made between DNA fingerprints of Mycobacterium tuberculosis produced with the insertion sequence IS6110 and those produced with the polymorphic GC-rich repetitive sequence contained in the plasmid pTBN12. A total of 302 M. tuberculosis isolates from the prison system in Madrid, Spain, and the Denver Public Health Department (Denver, Colo.) were analyzed with the two probes. Both probes identified the same isolates in the same clusters when the fingerprints had six or more copies of IS6110. Analysis of isolates with unique IS6110 fingerprints demonstrated that they were unique with pTBN12. The pTBN12 probe had greater discriminating power in isolates having five or fewer copies of IS6110. Forty-seven isolates from Denver having fewer than five copies of IS6110 which were grouped in 11 clusters with identical fingerprint patterns were subdivided into 35 different patterns by pTBN12. Isolates with IS6110 fingerprints with more than six copies of IS6110 that differed from one another by only one or two hybridizing bands were analyzed with pTBN12. Most of these sets of isolates demonstrated identical patterns with pTBN12. However, some exceptions were observed, suggesting that those having nearly identical IS6110 patterns should not necessarily be included in the same cluster. Since IS6110 provides more polymorphism in the fingerprint, it is most useful in identifying isolates with unique fingerprint patterns and those in clusters in which the isolates contain six or more copies of the insertion. However, it is necessary to employ a secondary probe, such as pTBN12, to discriminate isolates with five or fewer copies of IS6110 and those with similar but not identical IS6110 patterns.

Multifocal cellulitis and monoarticular arthritis as manifestations of Helicobacter cinaedi bacteremia

Helicobacter cinaedi (formerly Campylobacter cinaedi) was first detected in the fecal flora of homosexual men. Since 1984, 11 case reports of H. cinaedi bacteremia have been published; most cases have presented as a nonspecific febrile illness in homosexual men infected with the human immunodeficiency virus (HIV). We identified seven additional cases of H. cinaedi bacteremia in two Denver hospitals within a 5-year period, which suggests that this illness is not as rare as was previously thought. Six of these cases of H. cinaedi bacteremia occurred in homosexual men who were infected with HIV. Four patients presented with the distinctive cutaneous manifestation of multifocal cellulitis, and two patients had monoarticular arthritis. Microbiological diagnosis of this infection was delayed by the slow growth of the bacterium in nonradiometric blood culture bottles. Although the patients' bacteremia was prolonged, their response to treatment was excellent. In contrast to campylobacter infections in HIV-infected patients, H. cinaedi bacteremia did not relapse after a course of effective therapy. H. cinaedi bacteremia should be suspected in HIV-infected individuals who present with an indolent febrile illness, particularly in the presence of multifocal cellulitis and/or arthritis.

Familial hyperinsulinism presenting in adults

Two adult siblings presented with recurrent syncope due to severe hyperinsulinemic hypoglycemia. Exploratory laparotomy in the elder sibling showed a grossly normal pancreas, but histologic examination revealed islet cell hyperplasia. Neither sibling has any evidence of the multiple endocrine neoplasia type 1 syndrome, nor is there any other family history to suggest this diagnosis. To our knowledge, this is the first report of adult-onset familial hyperinsulinism without other manifestations of multiple endocrine neoplasia type 1 syndrome. A simple provocative test for hyperinsulinism was also suggested by these cases. Because the initial patient related his symptoms to exercise, we used treadmill exercise in both patients to diagnose hyperinsulinism and observe its response to therapy.

Oxidant-mediated ciliary dysfunction. Possible role in airway disease

The effects of reactive species of oxygen on the airway are not well known. This study examined the effects of hydrogen peroxide (H2O2) on the structure and function of the airway epithelium. Tracheal rings were prepared from 200 g male rats. Damage to the airway epithelium was assayed by monitoring the ciliary beat frequency, the release of 51Cr, and histology. H2O2 at concentrations of 1.0 mM and above caused a very rapid decrease in ciliary beat frequency. After ten minutes' exposure to 1.0 mM, the ciliary beat frequency was 72 +/- 20 percent of control. Release of 51Cr was a less sensitive measure with significant release occurring after four hours of exposure to ciliotoxic concentrations of H2O2. Histologic changes were not evident within the experimental time period. All toxic effects of H2O2 were completely blocked by catalase. This study shows that H2O2 causes a rapid decline in ciliary activity and suggests that oxidant-mediated ciliary dysfunction could play a role in the pathogenesis of airway disease. The ciliary beat frequency provides a sensitive, physiologically relevant parameter for the in vitro study of these diseases.